Not exactly what you asked for, but for what is worth the white immigrant vote can be estimated. This obviously also includes west-Europeans, Canadians and middle-easterners.
According to the Cooperative Campaign Analysis Project in 2008 Obama got 54% of white immigrant two-party share, compared to 47% of the white non-immigrant share in that data-set (a bit higher than exit polls of 44%) and 77% of non-white immigrant vote. The sample of white immigrants was 214.
though you won't be able to download it, it costs $15000 to participate, a professor gave me the data.